Related Experiment Video
Updated: Oct 29, 2025
Monitoring Dynamic Growth of Retinal Vessels in Oxygen-Induced Retinopathy Mouse Model
Published on: April 2, 2021
International Classification of Retinopathy of Prematurity, Third Edition
Michael F Chiang1, Graham E Quinn2, Alistair R Fielder3
1National Eye Institute, National Institutes of Health, Bethesda, Maryland.
Insights
The International Classification of Retinopathy of Prematurity (ROP) has been updated to ICROP3, addressing challenges in classification, imaging, and treatment. This revision aims to standardize ROP care globally for improved research and clinical outcomes.
Area of Science:
- Ophthalmology
- Neonatology
Background:
- Retinopathy of Prematurity (ROP) classification requires updates due to evolving diagnostic and therapeutic landscapes.
- Existing ROP classification systems face challenges with subjectivity, new imaging technologies, and diverse global ROP patterns.
Purpose of the Study:
- To present the third revision of the International Classification of Retinopathy of Prematurity (ICROP3).
- To address limitations in current ROP classification, including subjectivity, advancements in ophthalmic imaging, and novel pharmacologic therapies.
- To incorporate global variations in ROP presentation and improve standardization of care.
Main Methods:
- An international expert committee representing 17 countries was convened.
- The committee utilized iterative videoconferences, online discussions, and in-person meetings to reach consensus.
- Evidence-based literature review and expert consensus formed the basis for the revised classification.
Main Results:
- ICROP3 retains core definitions of ROP (zone, stage, extent) while refining key metrics.
- Major updates include new definitions for posterior zone II, notch, stage 5 subcategorization, and a spectrum of vascular abnormalities.
- The classification introduces 'aggressive ROP' to encompass broader presentations and details ROP regression, reactivation, and long-term sequelae.
Conclusions:
- ICROP3 provides an updated standard for ROP classification, enhancing diagnostic consistency.
- The revised classification aims to improve the quality and standardization of ROP care worldwide.
- ICROP3 serves as a foundation for advancing ROP research and clinical practice globally.
Purpose:
The International Classification of Retinopathy of Prematurity is a consensus statement that creates a standard nomenclature for classification of retinopathy of prematurity (ROP). It was initially published in 1984, expanded in 1987, and revisited in 2005. This article presents a third revision, the International Classification of Retinopathy of Prematurity, Third Edition (ICROP3), which is now required because of challenges such as: (1) concerns about subjectivity in critical elements of disease classification; (2) innovations in ophthalmic imaging; (3) novel pharmacologic therapies (e.g., anti-vascular endothelial growth factor agents) with unique regression and reactivation features after treatment compared with ablative therapies; and (4) recognition that patterns of ROP in some regions of the world do not fit neatly into the current classification system.
Design:
Review of evidence-based literature, along with expert consensus opinion.
Participants:
International ROP expert committee assembled in March 2019 representing 17 countries and comprising 14 pediatric ophthalmologists and 20 retinal specialists, as well as 12 women and 22 men.
Methods:
The committee was initially divided into 3 subcommittees-acute phase, regression or reactivation, and imaging-each of which used iterative videoconferences and an online message board to identify key challenges and approaches. Subsequently, the entire committee used iterative videoconferences, 2 in-person multiday meetings, and an online message board to develop consensus on classification.
Main Outcome Measures:
Consensus statement.
Results:
The ICROP3 retains current definitions such as zone (location of disease), stage (appearance of disease at the avascular-vascular junction), and circumferential extent of disease. Major updates in the ICROP3 include refined classification metrics (e.g., posterior zone II, notch, subcategorization of stage 5, and recognition that a continuous spectrum of vascular abnormality exists from normal to plus disease). Updates also include the definition of aggressive ROP to replace aggressive-posterior ROP because of increasing recognition that aggressive disease may occur in larger preterm infants and beyond the posterior retina, particularly in regions of the world with limited resources. ROP regression and reactivation are described in detail, with additional description of long-term sequelae.
Conclusions:
These principles may improve the quality and standardization of ROP care worldwide and may provide a foundation to improve research and clinical care.
